Motorcycle with adjustable geometry

ABSTRACT

The invention is a motorcycle with a main frame ( 1 ), the main frame ( 1 ) holding a rear swing arm assembly ( 2 ) with a rear wheel assembly ( 3 ), said main frame ( 1 ) holding an engine ( 12 ) and a drive train ( 13 ) connected to the rear wheel assembly ( 3 ). The main frame ( 1 ) is connected via a pivot joint ( 9 ) near the main frame&#39;s ( 9 ) upper, fore portion to a top frame ( 7 ), and the pivot joint ( 9 ) has a transverse axis ( 9′ ) relative to the main frame ( 1 ). The top frame ( 7 ) has a rearwards extending seat frame ( 8 ) provided with a seat ( 15 ) and a forward extending steering neck frame ( 5 ) holding a steering neck ( 6 ) further holding a triple tree assembly ( 14 ) with a front fork assembly ( 4 ) with a front wheel assembly ( 10 ). The main frame ( 1 ) is provided with an actuator assembly ( 16 ) for providing rotation of the top frame ( 7 ) relative to the main frame ( 1 ). The actuator assembly ( 16 ) is connected at a first lower end ( 161 ) to a lower connection point ( 17 ) near a rear portion of the main frame ( 1 ), and connected at an opposite, second upper end ( 162 ) to an upper connection point ( 18 ) at the top frame ( 7 ). Thus the motorcycle may be adjusted for rake, trail and seat elevation between a racing sport configuration and a custom or “chopper” configuration through use of the actuator ( 16 ).

The present invention relates to a motorcycle. More specifically, theinvention relates to mechanisms for adjusting the front fork assemblygeometries relative to the main frame, and simultaneously adjusting theseat elevation relative to the main frame.

SUMMARY OF THE INVENTION

The invention is a motorcycle with a main frame, the main frame holdinga rear swing arm assembly with a rear wheel assembly, the main frameholding an engine and a drive train connected to the rear wheelassembly, the main frame connected via a pivot joint near the mainframe's upper, fore portion to a top frame, the pivot joint having atransverse axis relative to the main frame, the top frame having arearwards extending seat frame provided with a seat and a forwardextending steering neck frame holding a steering neck further holding atriple tree assembly with a front fork assembly with a front wheelassembly, the main frame provided with an actuator assembly forproviding rotation of the top frame relative to the main frame about thetransverse axis.

In a preferred embodiment, the actuator assembly is connected at a firstlower end to a lower connection point near a rear portion of the mainframe, and connected at an opposite, second upper end to an upperconnection point at the top frame.

FIGURE CAPTIONS

The invention is illustrated in the attached drawings.

FIG. 1 is a side elevation view of a stripped motorcycle with a mainframe holding an engine and a drive train assembly connected to a rearswing arm assembly with a rear wheel assembly, the main frame providedwith a pivotable top frame holding a combined seat frame and steeringneck frame, the steering neck frame holding a triple tree assemblyfurther holding a front fork assembly with a front wheel. An actuatorassembly for adjusting the angular position of the top frame relative tothe main frame is illustrated.

FIG. 2 is an enlarged view of the rear part of the main frame and theseat frame and the rear swing assembly, showing elements of the actuatorassembly.

FIG. 3 is an illustration of some important geometric features of thefront wheel assembly. The so-called trail (99) is the distance from thefront wheel contact point with the ground to the intersection of theaxis of the steering neck with the ground.

EMBODIMENTS OF THE INVENTION

An embodiment of a motorcycle of the invention is illustrated in FIG. 1.The motorcycle of the invention comprises a main frame (1) holding arear swing arm assembly (2) with a rear wheel assembly (3), the mainframe (1) holding an engine (12) and a drive train (13) connected to therear wheel assembly (3). The engine may be of the internal combustiontype, but may alternatively be an electric motor. The engine mayalternatively be arranged with the rear swing assembly.

Further, the main frame (1) is connected via a pivot joint (9) near themain frame's (1) upper, fore portion to a top frame (7). The pivot joint(9) has a transverse axis (9′) relative to said main frame (1). The topframe (7) has a rearwards extending seat frame (8) provided with a seat(15), and a forward extending steering neck frame (5) holding a steeringneck (6) further holding a triple tree assembly (14) with a front forkassembly (4) with a front wheel assembly (10).

Further, the main frame (1) is provided with an actuator assembly (16)for providing rotation of the top frame (7) relative to the main frame(1). The actuator assembly (16) is connected at a first lower end (161)to a lower connection point (17) near a rear portion of the main frame(1), and connected at an opposite, second, upper end (162) to an upperconnection point (18) at the top frame (7). In an embodiment of theinvention the connection point (18) at the top frame (7) is arranged atsaid seat frame (8).

For the front wheel assembly, the so-called trail (99) is the distancefrom the front wheel contact point with the ground to the intersectionof the axis of the steering neck with the ground, please see FIG. 3.This distance is important to the dynamic properties of the motorcycleand its handling characteristics. The so-called “rake” is the angle withthe vertical of the front forks. The trail should be in the rangebetween 50 mm and 150 mm. We may describe three different types ofmotorcycles having different rake angles and trail distances. First, asport racing type motorcycle generally has a 24 to 26 degrees rake angleand a corresponding trail distance of 65 to 80 mm. Second, an uprighttouring motorcycle may have a rake angle of 27 to 29 degrees and a traildistance of 75 to 110 mm. Third, a cruiser or “chopper” type motorcyclemay be provided with a front fork assembly with a rake angle of between30 and all the way up to 50 degrees (or more, in extreme embodiments)and a corresponding trail distance between 100 and 150 mm. A combinationof low figures of both rake and trail generally provides agile andaggressive driving and steering dynamics, while the opposite combinationof high figures provides calmer and more sedate handling characteristicsand steering dynamics.

A so-called sport racing motorcycle generally has a high seat, in therange between 780 mm and 820 mm. In the opposite range of the touring orcruising motorcycle segment, the seat height is in the range from 600 mmto 780 mm.

A general advantage of the invention is that the geometry of the frontwheel suspension assembly and the seat frame may simultaneously beadjusted relative to the main frame using the actuator. This provides amotorcycle with the capability of shape-shifting over a range of chassisconfigurations with rake and trail and seat height propertiescorresponding to the first, sport racing type motorcycle, the thirdcruiser or chopper type motorcycle, and intermediates. In an embodimentof the invention the top frame (7) may be rotated so as for the rake tobe about 24 degrees, the trail about 80 mm, and the seat height about800 mm for a so-called sport racing configuration. In the sameembodiment, the top frame may be rotated in an opposite direction so asfor the rake to be about 31 degrees, the trail to about 120 mm, and theseat height to be about 600 mm, for providing a cruiser configuration.

The actuator may be of any type suitable for rotating the top framerelative to the main frame. In an embodiment of the invention theactuator is of a linear type. The actuator may be of the hydraulic orpneumatic type, and would draw power from a pump connected to the mainengine, or of the electromechanichal type drawing power from theengine's generator or electrical accumulator. The person skilled in theart may select a suitable actuator at his or her discression.

In an embodiment of the invention the actuator (16) may be controlledfrom a rider operated control unit (19) which provides control signalsfor extending or contracting the length of the actuator (16) accordingto the driver's desire. The control unit (19) may in an embodiment be asingle or double electrical switch for running the actuator (16) in the“longer” or “shorter” direction, in order to adjust the motorcyclebetween a racing or cruising configuration, and possibly provided with a“stop” or “lock” position inbetween for setting the configurationreached.

In an embodiment of the invention the rear swing arm assembly (2) isprovided with a suspension and shock absorber assembly (20). Thesuspension and shock absorber assembly is connected at a first, lowerend (201) to the rear swing arm assembly (2) and at a second, upper end(202) to the rear portion of the main frame (1). In an embodiment of theinvention the second, upper end (202) of the suspension and shockabsorber assembly (20) is connected via a suspension pivot arm (21)extending rearwards from a suspension pivot joint (22) at the rearportion of the main frame (1). The suspension pivot arm (21) has aforward extension to a connecting joint (23) to a link arm (24) whichlinks to the top frame (7). In an embodiment the link arm (24) isconnected to the top frame (7) in the upper connection point (18) forthe upper end of the actuator assembly (16), please see FIG. 2.

An advantage of this arrangement of having the rear swing arm indirectlyconnected to the top frame is that an adjustment of the front fork raketo a steeper angle and a consequent elevation of the front end of themain frame above the ground will also result in a correspondingelevation of the rear part of the main frame, and will thus maintain theorientation of the main frame relative to the ground while the rideheight of the main frame is increased. Conversely, when the front forkrake is adjusted to a less steep angle, the rear part of the main framewill also be lowered, and the ride height will be lowered while theorientation of the main frame will be maintained.

1. A motorcycle comprising a main frame, said main frame holding a rearswing arm assembly with a rear wheel assembly, said main frame holdingan engine and a drive train connected to said rear wheel assembly, saidmain frame connected via a pivot joint near said main frame's upper,fore portion to a top frame, said pivot joint having a transverse axisrelative to said main frame, wherein said top frame having a rearwardsextending seat frame provided with a seat and a forward extendingsteering neck frame holding a steering neck further holding a tripletree assembly with a front fork assembly with a front wheel assembly,said main frame provided with an actuator assembly for providingrotation of said top frame relative to said main frame about saidtransverse axis.
 2. The motorcycle of claim 1, said connection point atsaid top frame arranged at said seat frame.
 3. The motorcycle of claim1, said rear swing arm assembly provided with a suspension and shockabsorber assembly connected at a first, lower end to said rear swing armassembly and at a second, upper end to a rear portion of said mainframe.
 4. The motorcycle of claim 1, said second, upper end of saidsuspension and shock absorber assembly connected via a suspension pivotarm extending rearwards from a suspension pivot joint at said rearportion of said main frame, said suspension pivot arm provided with aforward extension to a connecting joint to a link arm which links tosaid top frame.
 5. The motorcycle of claim 1, said link arm connected tosaid top frame in said upper connection point for said upper end of saidactuator assembly.
 6. The motorcycle of claim 1, said main frameprovided with an actuator assembly for providing rotation of said topframe relative to said main frame, said actuator assembly connected at afirst lower end to a lower connection point near a rear portion of saidmain frame, and connected at an opposite, second upper end to an upperconnection point at said top frame.
 7. The motorcycle of claim 2, saidrear swing arm assembly provided with a suspension and shock absorberassembly connected at a first, lower end to said rear swing arm assemblyand at a second, upper end to a rear portion of said main frame.
 8. Themotorcycle of claim 2, said second, upper end of said suspension andshock absorber assembly connected via a suspension pivot arm extendingrearwards from a suspension pivot joint at said rear portion of saidmain frame, said suspension pivot arm provided with a forward extensionto a connecting joint to a link arm which links to said top frame. 9.The motorcycle of claim 3, said second, upper end of said suspension andshock absorber assembly connected via a suspension pivot arm extendingrearwards from a suspension pivot joint at said rear portion of saidmain frame, said suspension pivot arm provided with a forward extensionto a connecting joint to a link arm which links to said top frame. 10.The motorcycle of claim 2, said link arm connected to said top frame insaid upper connection point for said upper end of said actuatorassembly.
 11. The motorcycle of claim 3, said link arm connected to saidtop frame in said upper connection point for said upper end of saidactuator assembly.
 12. The motorcycle of claim 4, said link armconnected to said top frame in said upper connection point for saidupper end of said actuator assembly.
 13. The motorcycle of claim 2, saidmain frame provided with an actuator assembly for providing rotation ofsaid top frame relative to said main frame, said actuator assemblyconnected at a first lower end to a lower connection point near a rearportion of said main frame, and connected at an opposite, second upperend to an upper connection point at said top frame.
 14. The motorcycleof claim 3, said main frame provided with an actuator assembly forproviding rotation of said top frame relative to said main frame, saidactuator assembly connected at a first lower end to a lower connectionpoint near a rear portion of said main frame, and connected at anopposite, second upper end to an upper connection point at said topframe.
 15. The motorcycle of claim 4, said main frame provided with anactuator assembly for providing rotation of said top frame relative tosaid main frame, said actuator assembly connected at a first lower endto a lower connection point near a rear portion of said main frame, andconnected at an opposite, second upper end to an upper connection pointat said top frame.
 16. The motorcycle of claim 5, said main frameprovided with an actuator assembly for providing rotation of said topframe relative to said main frame, said actuator assembly connected at afirst lower end to a lower connection point near a rear portion of saidmain frame, and connected at an opposite, second upper end to an upperconnection point at said top frame.